In the framework of reducing GHG emissions and accelerating the decarbonization of the road transport sector, vehicle efficiency is a key factor for competitiveness. In this sense, the refining industry can make its contribution by reformulating high-octane petrol fuel. The impact of this type of gasoline from CO₂ emission balance, technical feasibility, and economics standpoints has recently been assessed by the petroleum industry with promising results, and new potential boosters that could improve the octane number of standard gasoline are more needed than ever. The present work summarizes a comprehensive review aimed at collecting available data regarding chemical molecules that can be used in advanced gasoline formulations for modern spark-ignited car engines focusing on ash-free technologies. Potential boosters are divided into two categories: high-octane gasoline components and octane enhancer additives, with 2 vol % the considered frontier concentration between them. Targeted chemical compounds examined in the screening for high-octane components include isoparaffins, olefins, aromatics, alcohols, ethers, esters, ketones, furans, and carbonates. Chemical families assessed as additives were anilines, hydrazines, amines, pyridines, quinolines, indoles, N-nitrosamines, iodine compounds, selenium compounds, phenols, formates, oxalates, and, in lesser extension, other families. The scope of the analysis includes not only anti-knock effectiveness but also associated side effects for the engine, possible effects on both human health and the environment, current applications, and compatibility with existing infrastructure, among others. Promising opportunities in the medium- and long-terms for every family of chemical compounds that can potentially improve the anti-knock character of modern gasolines well beyond current specifications worldwide are presented. Furthermore, a few chemical families are identified as the most promising ones to be used in future gasoline formulations, either as high-octane components (such as ethers, ketones, and esters) or as octane booster additives (such as anilines, N-nitrosamines, and phenols).

Although macroreticular acidic ion-exchange resins have been widely used as catalysts in the industrial world for decades, their catalytic behavior is still far from being completely understood at a molecular level. Several characterization techniques coexist, which provide information about their properties. Only few of these techniques give an actual picture of their working-state features when swollen in anhydrous polar reactive media such as in etherification processes, where they are extensively used. The inverse steric exclusion chromatography technique, based on modeling the micropores structure, or gel-phase, as a set of discrete volume fractions with a characteristic polymer chain density, constitutes an appropriate procedure to assess the morphology of ion-exchangers in the swollen state. Present work proposes an empirical model to correlate the properties of the volume fractions with their catalytic activity in the etherification reaction rates of isobutene by addition of C1–C4 linear primary alcohols. Sixteen different macroreticular acidic ion-exchange catalysts, both commercial and lab-made, have been used, which differ in acid capacity, sulfonation type, cross-linking degree and swollen-phase volume fractions distribution. Experimental reaction rates have been expressed as a sum of contributions of each individual volume fraction. The contribution of each polymer volume fraction corresponds to the product of the catalyst acidity, the characteristic volume fraction within the gel-phase of the catalyst, and a specific turnover frequency of that fraction. Accessibility of the reacting alcohol, expressed in terms of the Ogston coefficient, has been also included in the empirical dependency equation presented in this work.

The role of ion-exchange resins (IERs) as catalysts or catalysts supports, in hydrogenation reactions is revised and their potential application is presented. Both gel-type and macroreticular, basic or acid, IERs have been used for manifold metal-catalyzed hydrogenation processes in gas and liquid phase, including hydrogenation of alkenes, alkynes, carbonyls, arenes, nitroaromatics, and more. When available, qualitative relationships between the morphology and structure of resins and their performance as solid supports for metal catalysts are observed. Noble metals, such as Pt, Au, and Pd, and non-noble metals, such as Fe and Cu, have been introduced into IERs polymeric backbones by simple ion-exchange of a metal salt precursor with the resin, or by a combination of ion-exchange and other protocols, to obtain mono- and bimetallic catalysts supported on IERs. High yields towards target product, as well as the recyclability of metal-doped IERs, have been reported in the literature, with low metal leaching, which makes them highly interesting solid catalysts for a wide array of industrial applications. Multistep reaction processes, involving hydrogenation and hydration/cyclization/aldol condensation/etc., constitute promising applications due to the one-pot synthesis approach and relatively low temperatures required, which adds environmental interest in terms of process integration and optimization.